1. Field of the Invention
The present invention relates to a digital broadcasting system.
2. Description of the Related Art
Digital broadcasting has been developed in recent years so that a wide variety of programs can be provided on a large number of channels. For satellite digital broadcasting, large numbers of channels are possible by multiplexing the channels together into a single frequency band. This multiplexing is performed using what is called a xe2x80x9ctransport streamxe2x80x9d under MPEG2 (Moving Pictures Experts Group2) standard. This technique is described in detail in the documentation for ISO/IEC Standard 13818-1 (MPEG2 system).
These satellite digital broadcasts consist of the one-way transmission of image information and other data from a transmitter station, so that no interaction with the receiver is possible. However, a greater variety of services would be possible if it were possible to enable the user of a receiver terminal to perform interactive operations for the image information.
As a result, various interactive systems have developed which use a telephone line or the like to connect the receiver terminal to the transmitter station. However, these systems require the provision of a separate communication line between each receiver terminal and the transmitter station, incurring significant connection charges.
In view of the stated problems, it is a primary object of the present invention to provide digital broadcasting system which can achieve the effects of interactive reproduction of received image information in a two-way communication system using image information which is transmitted by a transmitter in a one-way communication system.
The stated object can be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for a corresponding set of image data; and a transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of sets of the control information.
The stated object can also be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for a corresponding set of image data; and a multiplexing transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of sets of the control information as a multiplexed stream.
With the stated construction, a user can freely switch from a displayed set of image data to another set of image data in accordance with the link destination information when image data is one-directionally transmitted from a digital broadcasting apparatus. An interactive digital broadcast can thereby be achieved.
Here, the digital broadcasting apparatus may also include a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data and the sets of control information, the multiplexing transmission unit including a retrieval unit for retrieving a set of image data and a corresponding set of control information shown in the correspondence information, and a multiplexing unit for successively multiplexing image data and control information retrieved by the retrieval unit.
With the stated construction, a plurality of sets of image data and control information can be repeatedly transmitted.
Here, the link destination information may show a combination of an image data identifier of the set of the image data for the link destination and a control information identifier of a corresponding set of control information for the link destination.
With the stated construction, the image data of a link destination and the corresponding control information can be specified.
Here, the multiplexing unit, when multiplexing a set of image data and a set of control information, may assign and write first image data identification information into the set of image data and control information identification information into the set of control information.
With the stated construction, a digital broadcast reception apparatus can extract a desired set of image data and control information using the respective sets of identification information.
Here, at least one set of control information may include supplementary image information which is used to select a set of image data for a link destination indicated by the link destination information.
With the stated construction, interactive operations can be easily achieved by the user.
Here, at least one set of control information may include script information for supporting an interactive function performed by a reception apparatus which receives the digital broadcast.
With the stated construction, the interactive function of the digital broadcast reproduction apparatus can be better supported.
Here, the digital broadcasting apparatus may also include an entry information storage unit for storing entry information which shows a combination of a set of image data and a set of control information which are to be reproduced first for a program, with the multiplexing transmission unit repeatedly transmitting the entry information.
With the stated construction, the image data and control information which are to be reproduced at the start of a program can be clearly established, thereby facilitating user interactive operations by the digital broadcast reception apparatus.
The stated object can also be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for a corresponding set of image data, the link destination information showing a combination of an image data identifier of the set of the image data for the link destination and a control information identifier for the set of the control information; a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data and the sets of control information; and a multiplexing transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of the control information as a multiplexed stream, the multiplexing transmission unit including: a retrieval unit for retrieving a set of image data and a corresponding set of control information shown in the correspondence information; a multiplexing subunit for successively multiplexing image data and control information retrieved by the retrieval unit, in doing so assigning and writing first image data identification information into the set of image data and control information identification information into the set of control information, an image correspondence table generation unit for generating an image correspondence table for each set of image data, each image correspondence table being given identification information found from the image data identifier of the corresponding set of image data, each image correspondence table including second image data identification information specifying a corresponding set of image data; and an image correspondence table multiplexing unit for reading an image correspondence table corresponding to a set of image data and multiplexing the image correspondence table such that the image correspondence table will be transmitted by the multiplexing transmission unit at a time which precedes a transmission of the corresponding set of image data by at least a predetermined time period, the predetermined time period being defined as a time period which allows a digital broadcast reception apparatus which receives the digital broadcast to obtain the second image data identification information specifying a set of image data before starting to extract the corresponding set of image data.
With the stated construction, the image correspondence tables are referred to by a digital broadcast reception apparatus so that it can then properly extract the image data. The digital broadcast reception apparatus is also able to make effective use of the first and second image data identification information and, despite using small amounts of identification information, is able to verify the correspondence between image data and image correspondence tables, even when there are many sets of image data, some of which are assigned the same identification information.
Here, the multiplexing transmission unit may further include a retrieval control unit for controlling the retrieval unit to retrieve at least one set of image data which has first image data identification information that differs from the image data specified by second image data identification information included in the image correspondence table, during a time period between a multiplexing of the image correspondence table into the multiplexed stream by the image correspondence table multiplexing unit and a multiplexing of the set of image data corresponding to the image correspondence table.
With the stated construction, the efficiency of the transmission of image data can be improved.
Here, the multiplexing subunit may include a null data generation unit for generating, when a number of sets of image data stored in the image information storage unit is less than a predetermined number, a number of sets of null data to make up the predetermined number, with the multiplexing subunit successively multiplexing the sets of null data generated by the null data generation unit after a final set of image data and a final set of control information have been read by the retrieval unit.
With the stated construction, an interval time which is no shorter than a predetermined transmission time interval is maintained between the transmission of an image correspondence table and the corresponding image data. By doing so, the desired image data can be properly extracted by the digital broadcast reception apparatus.
Here, the multiplexing subunit may further include an area assigning unit for assigning, when a set of image data and a set of control information are multiplexed, a bit rate to the set of image data and to the corresponding set of control information, each bit rate being determined in accordance with a ratio of a data amount of each set of image data to an information amount of the corresponding set of control information, and the multiplexing subunit may multiplex the set of image data and the set of control information using the respective bit rates assigned by the area assigning unit.
With the stated construction, the control information corresponding to the image data can be transmitted at approximately the same time, so that the digital broadcast reception apparatus will be able to extract the image data and control information at roughly the same time.
Here, the multiplexing subunit may further include a multiplexing start position calculation unit for calculating multiplexing start positions for when an image correspondence table, a set of image data, and a set of control information are multiplexed, using a predetermined equation, with the image correspondence table multiplexing unit multiplexing an image correspondence table starting at the multiplexing start position calculated by the multiplexing start position calculation unit, and the multiplexing subunit multiplexing a set of image data and a set of control information at the respective multiplexing start positions calculated by the multiplexing start position calculation unit.
With the stated construction, the multiplexing start positions of sets of image data, sets of control information, and image correspondence tables can be clearly established.
Here, the first image data identification information and the second image data identification information may be the same.
Here also, the first image data identification information and the second image data identification information may also be combinations of a stream identifier (xe2x80x9cstream_idxe2x80x9d) and a packet identifier (xe2x80x9cPIDxe2x80x9d) in accordance with MPEG2 (Moving Pictures Experts Group2) standard.
With the stated construction, the digital broadcast reception apparatus is able to extract sets of image data without referring to a correspondence table.
Here, the first image data identification information may be a combination of a stream identifier (xe2x80x9cstream_idxe2x80x9d) and a packet identifier (xe2x80x9cPIDxe2x80x9d) in accordance with MPEG2 (Moving Pictures Experts Group2) standard, and the second image data identification information may be a combination of a stream identifier in accordance with MPEG2 (Moving Pictures Experts Group2) standard and a component tag (xe2x80x9ccomponent_tagxe2x80x9d) in accordance with DVB (Digital Video Broadcasting) standard, with the multiplexing transmission unit repeatedly transmitting a correspondence table for the packet identifier and the component tag.
With the stated construction, the image data can be indirectly specified using the image correspondence table, so that even if the packet identifiers assigned to image data are changed by the digital broadcast system, the digital broadcast reception apparatus will be able to refer to the image correspondence table, obtain the first image data identification information, and use this to obtain the desired image data.
Here, the multiplexing transmission unit may further include an image data identifier appending unit for writing, when a set of image data retrieved by the retrieval unit is multiplexed, an image data identifier into a private area of the corresponding set of image data.
With the stated construction, the digital broadcasting reception apparatus can judge whether it has extracted the correct set of image data.
Here, the image correspondence table multiplexing unit, after multiplexing an image correspondence table, may multiplex the same image correspondence table a plurality of times before a set of image data which corresponds to the image correspondence table is multiplexed.
With the stated construction, the digital broadcast reception apparatus may reproduce image data at high speed when its load is not substantial.
Here, the stated object can also be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; an audio information storage unit for storing a plurality of sets of audio data, each of which has an audio data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data, a set of audio data, and a set of control information for a link destination for the corresponding set of image data; and a multiplexing transmission unit for repeatedly transmitting a plurality of sets of the image data, a plurality of sets of audio data, and a plurality of the control information as a multiplexed stream.
With the stated construction, audio data can be subjected to interactive operations by the digital broadcast reception apparatus, in addition to image data.
Here, the digital broadcasting apparatus may further include a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data, the sets of audio data, and the sets of control information, and the multiplexing transmission unit may include a retrieval unit for retrieving a set of image data and a corresponding set of audio data and a corresponding set of control information shown in the correspondence information and a multiplexing unit for successively multiplexing image data, audio data and control information retrieved by the retrieval unit.
With the stated construction, a plurality of sets of image data, a plurality of sets of audio data, and a plurality of sets of control information can be repeatedly transmitted.
Here, the link destination information may show a combination of an image data identifier for the set of image data of a link destination, an audio data identifier for the set of audio data of the link destination, and a control information identifier for the control information of the link destination.
With the stated construction, the audio data of the link destination and the corresponding control information can be specified.
Here, when multiplexing a set of image data, a set of audio data, and a set of control information, the multiplexing unit may assign and write first image data identification information into the set of image data, first audio data identification information into the set of audio data, and control information identification information into the set of control information.
With the stated construction, a desired set of audio data can be extracted using the identification information.
Here, the multiplexing transmission unit may further include: an image correspondence table generation unit for generating an image correspondence table for each set of image data, each image correspondence table being given identification information found from the image data identifier of the corresponding set of image data, each image correspondence table including second image data identification information specifying a corresponding set of image data; an audio correspondence table generation unit for generating an audio correspondence table for each set of audio data, each audio correspondence table being given identification information found from the audio data identifier of the corresponding set of audio data, each audio correspondence table including second audio data identification information specifying a corresponding set of audio data, an image correspondence table multiplexing unit for reading an image correspondence table corresponding to a set of image data and multiplexing the image correspondence table such that the image correspondence table will be transmitted by the multiplexing transmission unit at a time which precedes a transmission of the corresponding set of image data by at least a predetermined time period, the predetermined time period being defined as a time period which allows a digital broadcast reception apparatus which receives the digital broadcast to obtain the second image data identification information specifying a set of image data before starting to extract the image data; and an audio correspondence table multiplexing unit for reading an audio correspondence table corresponding to a set of audio data and multiplexing the audio correspondence table such that the audio correspondence table will be transmitted by the multiplexing transmission unit at a time which precedes a transmission of the corresponding set of audio data by at least a predetermined time period, the predetermined time period being defined as a time period which allows a digital broadcast reception apparatus which receives the digital broadcast to obtain the second audio identification information specifying a set of audio data before starting to extract the audio data.
With the stated construction, the digital broadcast reception apparatus is able to refer to the image correspondence table and the audio correspondence table and properly extract the desired image data and audio data.
The stated object can also be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for the sets of image data, the link destination information showing a combination of an image data identifier of the set of the image data for the link destination and a control information identifier for the set of control information; a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data and the sets of control information; and a multiplexing transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of the control information as a multiplexed stream, the multiplexing transmission unit including: a retrieval unit for retrieving a plurality of sets of image data and corresponding sets of control information shown in the correspondence information; a multiplexing subunit for successively multiplexing image data and control information retrieved by the retrieval unit, in doing so assigning and writing first image data identification information into the set of image data and control information identification information into the set of control information; an image correspondence table generation unit for generating an image correspondence table for each set of image data, using a value equal to the image data identifier of the set of image data as the identification information of the image correspondence table, each image correspondence table including second image data identification information specifying a corresponding set of image data and reproduction time information for the corresponding set of image data; and an image correspondence table multiplexing unit for reading an image correspondence table corresponding to a set of image data and multiplexing the image correspondence table such that the image correspondence table will be transmitted by the multiplexing transmission unit at a time which precedes a transmission of the corresponding set of image data by at least a predetermined time period, the predetermined time period being defined as a time period which allows a digital broadcast reception apparatus which receives the digital broadcast to obtain the second image data identification information specifying a set of image data before starting to extract the image data.
With the stated construction, the digital broadcast reception apparatus can be informed of time information for the reproduction of the image data.
Here, the image correspondence table generation unit may include: a reproduction time calculation unit for calculating reproduction time information at which a set of image data corresponding to an image correspondence table is to be reproduced, in accordance with a predetermined equation; and a reproduction time writing unit for writing the reproduction time information calculated by the reproduction time calculation unit into the image correspondence table.
With the stated construction, the timing of the extraction and reproduction of image data by the digital broadcast reception apparatus can be properly managed.
The stated object can also be achieved by a digital broadcasting apparatus which achieves simulated interaction using a digital broadcast, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for the sets of image data, the link destination information showing a combination of an image data identifier of the set of the image data for the link destination and a control information identifier for the control information; a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data and the sets of control information; and a multiplexing transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of the control information as a multiplexed stream, the multiplexing transmission unit including: a retrieval unit for retrieving a plurality of sets of image data and corresponding sets of control information shown in the correspondence information; a multiplexing unit for successively multiplexing image data and control information retrieved by the retrieval unit, in doing so assigning and writing first image data identification information into the set of image data and control information identification information into the set of control information; a module information generation unit for generating a set of module information for a plurality of sets of image data, the module information including second image data identification information for identifying each set of image data in the plurality of sets of image data; and a module information multiplexing unit for reading module information generated by the module information generation unit and multiplexing the module information such that the module information will be transmitted by the multiplexing transmission unit at a time which precedes a transmission of the sets of image data, which are identified by the second image data identification information in the module information, by at least a predetermined time period, the predetermined time period being defined as a time period which allows a digital broadcast reception apparatus which receives the digital broadcast to obtain the second image data identification information specifying a set of image data before starting to extract the corresponding set of image data.
With the stated construction, the digital broadcast reception apparatus is able to extract the proper set of image data by referring to the module information.
The stated object can also be achieved by a digital broadcast reception apparatus for receiving a repeatedly transmitted digital broadcast of a plurality of sets of image data and sets of control information which correspond to the sets of image data, each set of control information including link destination information showing a set of image data which is a link destination for a link attached to a set of image data corresponding to the set of control information, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast; a storage unit for storing the extracted set of control information; a reproduction unit for reproducing the extracted set of image data; an operation unit for receiving a user selection operation of link destination information included in the set of control information; and an extraction control unit for controlling the extraction unit to extract a set of image data and a corresponding set of control information which are indicated by the link destination information selected by the user selection operation.
With the stated construction, a user can freely switch from a displayed set of image data to another set of image data in accordance with the link destination information included in the control information when image data is one-directionally transmitted from a digital broadcasting apparatus. An interactive digital broadcast can thereby be achieved.
Here, each set of image data may be appended with first image data identification information and each set of control information may be appended with control information identification information, the operation unit including an indication reception unit for receiving an operation indicating a switching from a currently displayed set of image data to a set of image data for a link destination, the extraction control unit reading the link destination information in the set of control information stored in the storage unit, and setting an extraction condition for the extraction unit based on an image data identifier for a set of image data of the link destination to which switching has been indicated by the indication reception unit and a control information identifier for a corresponding set of control information, each set of control information including an image data identifier for identifying a set of image data for a link destination and a control information identifier for identifying a set of control information for the link destination as the link destination information, the extraction unit extracting a set of image data and a set of control information according to the extraction condition set by the extraction control unit.
With the stated construction, the digital broadcast reception apparatus can extract the desired image data and corresponding control information sent from the digital broadcasting apparatus according to the user switching indication for image data.
Here, the plurality of sets of image data and plurality of sets of corresponding control information are transmitted having been multiplexed into a multiplexed stream, the reproduction unit including a supplementary image reproduction unit for combining supplementary image information included in the control information stored in the storage unit with a set of image data and reproducing the combined image, the supplementary image information including a supplementary image which is used to select a switching of image data from a present set of image data to a link destination set of image data.
With the stated construction, the user can easily make image data switching indications to link destinations while viewing supplementary images on the display screen.
Here, the plurality of sets of image data and plurality of sets of corresponding control information may be transmitted having been multiplexed into a multiplexed stream, and each set of control information may include script information for supporting an interactive function, the reproduction unit including: a script information interpreting unit for interpreting script information; and a script execution unit for executing scripts in the script information, in accordance with an interpretation of the script information interpreting unit.
With the stated construction, user interactive functions can be easily realized by executing the scripts.
Here, the plurality of sets of image data and corresponding sets of control information may be transmitted having been multiplexed into a multiplexed stream, with entry information, showing an image data identifier of a set of image data to be reproduced first when the reproduction of the multiplexed stream is commenced and a control information identifier of a set of control information corresponding to the set of image data, being multiplexed into the multiplexed stream, the extraction unit including an entry information extraction unit for receiving an indication from the extraction control unit and extracting the entry information, with the storage unit including an entry information storage unit for storing the entry information extracted by the entry information extraction unit, and the extraction control unit setting the extraction condition in the extraction unit based on the image data identifier and the control information identifier written in the entry information.
With the stated construction, the set of image data and control information which are to be reproduced at the start of the reproduction of the multiplexed stream can be clearly established.
The stated object can be achieved by a digital broadcast reception apparatus for receiving a repeatedly transmitted digital broadcast of a plurality of sets of image data and sets of control information which correspond to the sets of image data, each set of control information including link destination information showing a set of image data which is a link destination for a link attached to a set of image data corresponding to the set of control information, each set of image data having first image data identification information, each set of control information having control information identification information, the plurality of sets of image data and corresponding sets of control information being multiplexed into a multiplexed stream and transmitted, the multiplexed stream including an image correspondence table for each set of image data, each image correspondence table including second image data identification information specifying a corresponding set of image data, each image correspondence table having identification information found from the image data identifier of the corresponding set of image data, the image correspondence tables being repeatedly transmitted in the same way as the sets of image data, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast, the extraction unit including an image correspondence table extraction unit for extracting an image correspondence table with the image correspondence table identification information which matches a set extraction condition; a storage unit for storing the extracted set of control information, the storage unit including an image correspondence table storage unit for storing the extracted image correspondence table; a reproduction unit for reproducing an extracted set of image data; an operation unit for receiving user selection operations for link destination information included in sets of control information, the operation unit including an indication receiving unit for receiving an indication for a switching from a set of image data presently being reproduced to a set of image data for a link destination; and an extraction control unit for controlling the extraction unit to extract a set of image data and a set of corresponding control information indicated by the link destination information included in the control information, for reading the link destination information in the set of control information stored in the storage unit, and for setting an extraction condition in the extraction unit based on an image data identifier of a set of image data of a link destination to which switching has been indicated by the indication receiving unit and a control information identifier of a corresponding set of control information, each set of control information including an image data identifier of a set of image data of a link destination and a control information identifier of a corresponding set of control information as the link destination information, the extraction unit extracting a set of image data and a set of control information indicated by the extraction condition in the extraction unit, and the extraction control unit including an extraction condition setting unit for setting image correspondence table identification information found from an image data identifier of a set of image data of the link destination as the extraction condition.
The extraction control unit may further include: an image data extraction control unit for reading the second image data identification information written in the image correspondence table stored in the image correspondence table storage unit and setting the extraction condition in the extraction unit using the read second image data identification information, and-the extraction unit may further include an image data extraction unit for extracting a set of image data which matches the extraction condition set by the image data extraction control unit.
With the stated construction, the digital broadcast reception apparatus can refer to the image correspondence table and obtain second image data identification information to indirectly specify the desired set of image data which it then extracts.
Here, the sets of image data may be such that identical first image data identification information have been repeatedly assigned to different sets of image data, and the reproduction unit may include an identifier extraction unit for extracting an image data identifier included in the image data extracted by the image data extraction unit, the image data identifier having been written into a private area of the image data, the extraction control unit may further include: an image data judgement unit for judging whether the image data identifier of the set of image data extracted by the image data extraction unit matches the image data identifier of the set of image data for the link destination in the read link destination information; a reproduction termination indicating unit for sending, when the image data judgement unit judges that the identifiers do not match, the reproduction unit an indication to terminate reproduction, with the reproduction unit terminating the reproduction on receiving the indication; and an image correspondence table extraction indicating unit for indicating an extraction of an image correspondence table to the image correspondence table extraction unit when the reproduction termination indicating unit has sent a reproduction termination indication.
With the stated construction, when a plurality of sets of image data have the same first image data identification information, the digital broadcast reception apparatus can properly extract the desired image data even when other data is first mistakenly extracted.
Here, the extraction control unit may further include an extraction termination indicating unit for indicating a termination of an extraction of a set of image data by the image data extraction unit when the image data judgement unit judges that the identifiers match, with the image data extraction unit terminating the extraction on receiving the indication.
With the stated construction, once a desired set of image data has been extracted, the extraction of other sets of image data is prevented.
Here, each image correspondence table may include a reproduction start time for the corresponding set of image data, and the reproduction unit may further include: a clock unit for measuring time, the reproduction unit decoding and reproducing the extracted set of image data, in doing so notifying the extraction control unit of a completion of decoding on completing a decoding of one set of image data, the extraction control unit also including: a reproduction start time judgement unit for judging whether a notification of the completion of decoding has been received from the reproduction unit before the reproduction start time of the set of image data written in the image correspondence table; and an extraction indicating unit for indicating a termination of an extraction of image data to the image data extraction unit when the reproduction start time judgement unit judges that no notification has been received, and for indicating an extraction of an image correspondence table to the image correspondence table extraction unit.
With the stated construction, reproduction which starts midway through the image data can be prevented.
Here, the first image data identification information may be a combination of a stream identifier (xe2x80x9cstream_idxe2x80x9d) and a packet identifier (xe2x80x9cpacket_idxe2x80x9d) according to MPEG2 (Moving Pictures Experts Group2) standard, the second image data identification information may be a combination of a stream identifier in accordance with MPEG2 standard and a component tag (xe2x80x9ccomponent_tagxe2x80x9d) in accordance with DVB (Digital Video Broadcasting) standard, and a correspondence table for the component tags and packet identifiers may be multiplexed into the multiplexed stream and repeatedly transmitted, with the extraction unit extracting the correspondence table and the extraction control unit referring to the correspondence table, converting the second image data identification information to the first image data identification information, and setting the extraction condition in the image data extraction unit.
With the stated construction, the digital broadcast reception apparatus can extract image data which has been multiplexed into the multiplexed stream according to MPEG2 standard.
Here, the control information identification information may be a table identifier extension (xe2x80x9ctable_id_extensionxe2x80x9d), in accordance with MPEG2 standard, which has a same value as the control information identifier.
With the stated construction, the digital broadcast reception apparatus can properly extract the control information.
Here, the first image data identification information and the second image data identification information may be identical, with the image data extraction control unit setting the read second image data identification information as the extraction condition in the extraction unit.
With the stated construction, the digital broadcast reception apparatus can set the second image data identification information of the image correspondence table as the extraction condition, meaning that the desired image data can be properly extracted.
Here, a reproduction end time of the corresponding set of image data may be written into the image correspondence table, with the reproduction unit further including a clock unit for measuring time, and the extraction control unit may further include: an end time judgement unit for judging whether the reproduction end time written in the image correspondence table has been reached; and an extraction termination indicating unit for indicating a termination of extraction of a set of image data to the image data extraction unit, when the end time judgement unit judges that the reproduction end time has been reached.
With the stated construction, the digital broadcast reception apparatus can stop the extraction of image data whose reproduction time has already passed.
The stated object can also be achieved by a digital broadcast reception apparatus for receiving a repeatedly transmitted digital broadcast of a plurality of sets of image data and sets of control information which correspond to the sets of image data, each set of control information including link destination information showing a set of image data which is a link destination for a link attached to a set of image data corresponding to the set of control information, each set of image data having first image data identification information, each set of control information having control information identification information, the plurality of sets of image data and corresponding sets of control information being multiplexed into a multiplexed stream and transmitted, the multiplexed stream including an image correspondence table for each set of image data, each image correspondence table including second image data identification information specifying a corresponding set of image data, each image correspondence table having identification information found from the image data identifier of the set of image data, the image correspondence tables being repeatedly transmitted in the same way as the sets of image data, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast, the extraction unit including an image correspondence table extraction unit for extracting an image correspondence table with image correspondence table identification information which matches a set extraction condition, a reproduction end time for a corresponding set of image data being written in each image correspondence table, and an image data extraction unit for extracting sets of image data which match the set extraction condition from the multiplexed stream; a storage unit for storing the extracted set of control information, the storage unit including an image correspondence table storage unit for storing the extracted image correspondence table; a reproduction unit for reproducing an extracted set of image data, with the reproduction unit including a clock unit for measuring time; an operation unit for receiving user selection operations for link destination information included in sets of control information, the operation unit including an indication receiving unit for receiving an indication for a switching from a set of image data presently being reproduced to a set of image data for a link destination; and an extraction control unit for controlling the extraction unit to extract a set of image data and a set of corresponding control information indicated by the link destination information included in the control information, for reading the link destination information in the set of control information stored in the storage unit, and for setting an extraction condition in the extraction unit based on an image data identifier of a set of image data of a link destination to which switching has been indicated by the indication receiving unit and a control information identifier of a corresponding set of control information, with each set of control information including an image data identifier of a set of image data of a link destination and a control information identifier of a corresponding set of control information as the link destination information, with the extraction unit extracting a set of image data and a set of control information indicated by the extraction condition in the extraction unit, and the extraction control unit including an extraction condition setting unit for setting image correspondence table identification information found from an image data identifier of a set of image data as the extraction condition; an end time judgement unit for judging whether the reproduction end time of a set of image data which is written in the image correspondence table has been reached; and an extraction state control unit for controlling the image data extraction unit to extract sets of image data which correspond to the extraction condition from the multiplexed stream, for a time period from a setting of the extraction condition by the extraction condition setting unit to a point when the end time judgement unit judges that the reproduction end time of the image data has been reached.
With the stated construction, the extraction of sets of image data which match the extraction condition but whose reproduction times have already passed can be prevented.
The stated object can also be achieved by a digital broadcast reception apparatus for receiving a repeatedly transmitted digital broadcast of a plurality of sets of image data, a plurality of sets of audio data and sets of control information which each correspond to one set of image data and one set of audio data, each set of control information including link destination information showing a set of image data and a set of audio data of a link destination for a link attached to a set of image data corresponding to the set of control information, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data, one set of audio data and a corresponding set of control information from the received digital broadcast; a storage unit for storing the extracted set of control information; a reproduction unit for reproducing the extracted set of image data and extracted set of audio data; an operation unit for receiving a user selection operation of link destination information included in the set of control information; and an extraction control unit for controlling the extraction unit to extract a set of image data, a set of audio data, and a corresponding set of control information which are indicated by the link destination information selected by the user selection operation.
With the stated construction, audio data can be subjected to interactive operations, in addition to the image data.
The stated object can also be achieved by a digital. broadcast reception apparatus for receiving a repeatedly transmitted digital broadcast of a plurality of sets of image data and sets of control information which each correspond to one set of image data, each set of control information including link destination information showing a set of image data of a link destination for a link attached to a set of image data corresponding to the set of control information, each set of image data having first image data identification information, each set of control information having control information identification information, the plurality of sets of image data and corresponding sets of control information being multiplexed into a multiplexed stream and transmitted, a plurality of sets of module information, into which correspondence between a plurality of image data identifiers and a plurality of second image data identification information is written, being multiplexed into the multiplexed stream, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast, the extraction unit including a module information extraction unit for extracting module information after an extraction condition for module information has been set; a storage unit for storing the extracted set of control information, the storage unit including a module information storage unit for storing the extracted module information; a reproduction unit for reproducing an extracted set of image data; an operation unit for receiving user selection operations for link destination information included in sets of control information, the operation unit including an indication receiving unit for receiving an indication for a switching from a set of image data presently being reproduced to a set of image data for a link destination; and an extraction control unit for controlling the extraction unit to extract a set of image data and a set of corresponding control information indicated by the link destination information included in the control information, for reading the link destination information in the set of control information stored in the storage unit, and for setting an extraction condition in the extraction unit based on an image data identifier of a set of image data of a link destination to which switching has been indicated by the indication receiving unit and a control information identifier of a corresponding set of control information, each set of control information including an image data identifier of a set of image data of a link destination and a control information identifier of a corresponding set of control information as the link destination information, the extraction unit extracting a set of image data and a set of control information indicated by the extraction condition in the extraction unit, and the extraction control unit further including: an image data identifier judgement unit for judging whether there is an image data identifier, which matches an image data identifier of the set of image data of the link destination read from the link destination information, in the module information stored in the module information storage unit; an image data extraction control unit for reading, when the image data identifier judgement unit judges that a matching image data identifier is present, second image data identification information corresponding to the image data identifier from the module information and for setting an extraction condition for image data in the extraction unit, using the second image data identification information; and a module information re-extraction indicating unit for indicating an extraction of new module information to the module information extraction unit when the image data identifier judgement unit judges that a matching image data identifier is not present, with the module information extraction unit, on receiving an indication from the module information re-extraction indicating unit, extracting new module information, and updating the module information stored in the module information storage unit, at which point the image data identifier judgement unit performs a judgement for the updated module information.
With the stated construction, the digital broadcast reception apparatus can refer to the module information and extract a desired set of image data.
The stated object can also be achieved by a digital broadcasting system, which achieves simulated interaction using a digital broadcast, including a digital broadcasting apparatus and a digital reception apparatus, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for a corresponding set of image data; and a transmission unit for repeatedly transmitting a plurality of sets of the image data and a plurality of sets of the control information, the digital broadcast reception apparatus including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast; a storage unit for storing the extracted set of control information; a reproduction unit for reproducing the extracted set of image data; an operation unit for receiving a user selection operation of link destination information included in the set of control information; and an extraction control unit for controlling the extraction unit to extract a set of image data and a corresponding set of control information which are indicated by the link destination information selected by the user selection operation.
The stated object can also be achieved by a digital broadcasting system, which achieves simulated interaction using a digital broadcast, including a digital broadcasting apparatus and a digital reception apparatus, the digital broadcasting apparatus including: an image information storage unit for storing a plurality of sets of image data, each of which has an image data identifier; a control information storage unit for storing a plurality of sets of control information, each of which has a control information identifier, and each of which includes link destination information that shows a set of image data and a set of control information for a link destination for a corresponding set of image data, the link destination information being a combination of an image data identifier for the set of image data of the link destination and a control information identifier for the set of control information for the link destination; a correspondence information storage unit for storing correspondence information showing correspondence between the sets of image data and the sets of control information; and a multiplexing transmission unit for reading a set of image data and a corresponding set of control information given in the correspondence information, and for repeatedly transmitting the read set of image data and the read set of control information as a multiplexed stream, having assigned image data identification information-and written the image data identification information into the image data, and having assigned control information identification information and written the control information identification information into the control data, the digital broadcast reception unit including: a reception unit for receiving the digital broadcast; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast; a storage unit for storing the extracted set of control information; a reproduction unit for reproducing the extracted set of image data; an operation unit for receiving a user selection operation of link destination information included in the set of control information; and an extraction control unit for controlling the extraction unit to extract a set of image data and a corresponding set of control information which are indicated by the link destination information selected by the user selection operation.
With the stated construction, a user can freely switch from a displayed set of image data to another set of image data in accordance with the link destination information when image data is one-directionally transmitted from a digital broadcasting apparatus. An interactive digital broadcast system can thereby be achieved.
The stated object can also be achieved by a recording medium for use by a reception apparatus, the reception apparatus including: reception unit which receives a repeatedly transmitted digital broadcast of a plurality of sets of image data and sets of control information which correspond to the sets of image data, each set of control information including link destination information showing a set of image data which is a link destination for a link attached to a set of image data corresponding to the set of control information; an extraction unit for extracting one set of image data and a corresponding set of control information from the received digital broadcast; a storage unit for storing the extracted set of control information; reproduction unit for reproducing the extracted set of image data; an operation unit for receiving a user operation; and a program execution unit for executing a program recorded on the recording medium, the program including the following steps: a selection operation judgement step for judging a user selection operation for link destination information included in a set of control information; and an extraction control step for controlling the extraction unit to extract a set of image data and a corresponding set of control information indicated by link destination information selected by the user.
With the stated construction, a digital broadcast reception apparatus which is not equipped with an interactive function can use the stated recording medium and so allow a user to freely switch from a displayed set of image data to another set of image data in accordance with the link destination information when image data is one-directionally transmitted from a digital broadcasting apparatus. An interactive digital broadcast can thereby be achieved.